The use of geomembranes in lining and covering fluid containment structures, e.g., irrigation canals, can mitigate water loss due to seepage and evaporation. However, current membranes are associated with several disadvantages regarding their durability, installation, and cost.
With respect to durability, current geomembranes can be covered with concrete or other similar material when installed as fluid liners. This can increase the durability of these membranes over the long term, e.g., over 5-10 years more, as compared to geomembranes that are left uncovered and thus exposed. This is because exposed geomembranes are susceptible to damage from external forces such as animal traffic, construction equipment, vandalism, and the like. In addition, typical materials used for geomembranes differ in their ability to lay flat and remain flat as temperatures change, in their ability to conform to rough sub-grades and adjust to soil settlement without leaking, in their resistance to UV weathering and oxidation, in their ability to be properly and easily installed while maintaining watertight integrity, and in their ability to be repaired effectively with reasonable cost and effort.
With respect to installation, surveys suggest that approximately 25% of membrane leaks result from the process of installing these geomembranes in waterways or other fluid containment structures. Installation methods have been developed for these geomembranes in an attempt to achieve strong watertight splices. However, some methods require expensive tools while others use chemical (adhesive) bonding systems that may be sensitive to weather, temperature, humidity, and/or rain. Regardless of the splicing method used, field splicing can become the determining factor for the speed by which a lining can be installed and ultimately the success of the installation. Further, repairs during the life of the liner are often neglected or performed poorly because of the lack of equipment and/or experience of the person assigned to make the repairs. Furthermore, once current geomembranes reach the end of their lifecycle, they need to be disposed of, thus adding to the environmental concerns associated with disposing of this type of waste.
With respect to cost, current geomembrane materials used for fluid liners typically include: high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polyvinylchloride (PVC), flexible polypropylene (fPP), chlorosulphonated polyethylene (CSPE), ethylene-propylene diene monomer (EPDM), bituminous geomembrane (BGM), polyurea (PU), and/or Hypalon®. These materials are petroleum-derived products. As such, the cost of these materials closely correlates and depends on petroleum prices, which have been and will likely continue to be volatile. For example, oil prices spiked beyond $150/barrel during 2008. As such, the cost of current geomembrane materials is relatively unpredictable and likely to be relatively expensive.